Apparatus for a process for the protection of plant seeds

ABSTRACT

An apparatus for a process for wet-treating seeds with an acaricidal, fungicidal, insecticidal or nutritive agent which consists of a foam-forming apparatus comprising a first foam-formation chamber equipped with openings which allow a gas and the aqueous composition containing at least one nonphytotoxic foaming agent to be admitted and containing, downstream of these openings, at least one sieve, this first chamber continuing into a second chamber for compressing and structuring the foam, which ends in an outlet nozzle for the foam.

This application is a division of Ser. No. 08/410,645, filed Mar. 24,1995, now U.S. Pat. No. 5,527,760, which is a continuation of Ser. No.08/182,075, filed Jan. 13, 1994, now abandoned, which is a 371 ofPCT/EP92/01571 filed Jul. 11, 1992.

BACKGROUND OF THE INVENTION

It is known that the treatment of seeds leads generally to an increasein the relative moisture level of the seeds. However, seeds are verysensitive to moisture which activates their germination. The toleranceof grain to water varies according to the geographical origin ofproduction and the species of seeds. Therefore since treatment with aphytoprotection product is, for example, carried out in October forFebruary-March sowings, it must not bring about more than 1 to 2%moisture on average in order to avoid any premature start togermination.

Drying of the seeds after treatment may be employed, but this can alterthe germinating ability.

Treatment by finely sprayed suspensions in order to form a "mist" doesnot give satisfactory results because the cloud of droplets has atendency to move in a body and is deposited on the seeds in a tooheterogeneous fashion.

With the development of genetically improved seeds such as hybridwheats, which are thus more expensive, sowing methods are more and moreof the seed-by-seed type and no longer by the hand-sowing method (thisclassical technique requires, for conventional wheat, 150 to 200kg/hectare).

It is thus important that all the seeds present in sowing receive thesame quantity of treatment product. The homogeneity of the treatmentalso affects each grain which must be treated in a uniform manner;however, by the conventional processes, certain areas such as the seedfurrow are more difficult to reach and escape treatment. The untreatedpace constitutes a favoured access route for parasites.

Finally, for economic reasons and to protect the environment, one of theaims sought in the improvement of these treatments is a reduction in thequantity of active ingredient used by improving the efficiency.

SUMMARY OF THE INVENTION

Hence, the present invention relates to a process for thephytoprotection of plant seeds, wherein there is simultaneously appliedto the seeds,

on the one hand, at least one first liquid composition containing atleast one phytoprotection product, and

on the other hand, a foam formed from a second composition, containingat least one nonphytotoxic foaming agent,

the two compositions being brought separately into contact with theseeds while mixing for a period of time sufficient to ensure homogeneousand even coating of the said seeds.

The length of time during which the seeds are kept in contact with thetreatment compositions will vary as a function of the seed type and thephytoprotection product according to the parameters known to thoseskilled in the art.

The phytoprotection may be applied to plant seeds and more particularlyto those varieties which are of interest as agri-foodstuffs, such aswheat, maize, barley, oilseed rape, sunflower, beet, rice and soya, aswell as vegetable and flower seeds.

The seeds thus treated may optionally be pregerminated.

The plant species are defined, inter alia, by their developed surfacearea. This surface area can vary, for the same weight, as a function ofthe volume of the seed. It can vary between 20 m² and 500 m² per 100 kgof seeds.

The process according to the invention enables the foam volume to beincreased despite the presence of antifoaming agents present in all thespeciality chemicals intended for seed treatment (Slurry method). Inparticular, it makes it possible to retain, at the end of the operation,a quantity of foam which is constant whatever the concentration ofantifoaming substance contained in the treatment products and to obtainthe same results as if the antifoaming agents present had beendeactivated.

The use of foam for this type of seed treatment had not been carded outhitherto. It facilitates improvement of the covering power of thetreatment for the same volume of starting liquid.

In fact, to provide a continuous film of 50 micrometers on a surface, itis necessary to employ, with a liquid, a volume of 1 liter per 20 m² or25 liters per 500 m².

The simultaneous formation of foam at the time of phytoprotectiontreatment makes it possible to increase the entire volume developed bythe starting solutions and thus to be able to reduce the quantity ofwater used. With application in the form of a suspension, 800 ml ofsolution are used on average to treat 80 m² of seeds which would not beuniformly covered. With the phytoprotection process according to themethod prescribed, the 800 ml will enable 20 to 40 liters of foam to beobtained, permitting a homogeneous and uniform covering of the seeds. Inthis context the foam has a lathering effect.

The reduction in the quantity of solution to be used by this processresults in a lower moisture contribution in relation to the conventionalprocess. The measurement carried out on the seeds before and aftertreatment by the two compositions, of which one is in the form of foam,shows that their moisture content is virtually unchanged by thistreatment.

The drying stage is redundant and it is possible to proceed directly tothe bagging stage.

The simultaneous use of a foam and a phytoprotection product will alsoincrease the ability to penetrate into the areas of the seed which aredifficult to reach. Indeed, the seeds exhibit surface irregularitieswhich result in variations in interfacial tension, especially at thepericarp, upper scutellum, lower scutellum, hilum and pedicel.Conventional treatment methods do not reach the seed furrow and therecan be gaps in the protective coating on the seed.

The use of foam makes it possible to multiply the volume of the solutionby 20 to 50 and thus to favour seed/solution contact. The foam makes itpossible to increase the wettability of the areas of the seed which aredifficult to reach. This process thus leads to uniformity in thetreatment of each seed, all the seeds being treated.

This process is characterised in that the phytoprotection productcomprises an insecticidal, acaricidal and/or fungicidal and/or nutritiveactive ingredient, optionally combined with other additives which favourcontrolled germination and wetting, dispersing, colouring, adhesive andstabilising agents.

It is thus possible to use complex speciality chemicals asphytoprotection products.

Examples of suitable phytoprotection products, available commercially inthe form of formulations, are as follows:

    ______________________________________                                        (The abbreviations SC and WS stand for "suspension concentrate"               and "wettable powder for slurry treatment" respectively.                      The abbreviation q stands for "quintal", meaning 100 kg).                     ______________________________________                                        QUINOLATE + AC FL ®                                                       SC                                                                            Rate of use:         200 ml/q cereals                                         Composition:         100 g/l oxine-copper                                                          250 g/l anthraquinone                                    QUINOLATE PRO FL ®                                                        SC                                                                            Rate of use:         250 ml/q peas, soya,                                                          beans, sunflower                                         Composition:         120 g/l oxine-copper                                                          120 g/l carbendazim                                      CORMAISON FI ®                                                            SC                                                                            Rate of use:         500 ml/q maize                                           Composition:         200 g/l anthraquinone                                                         300 g/l captan                                           CORMAISON TX FL ®                                                         SC                                                                            Rate of use:         600 ml/q maize                                           Composition:         147 g/l anthraquinone                                                         150 g/l carboxin                                                              150 g/l thiram                                           CORMAISON X ®                                                             WS                                                                            Rate of use:         400 g/q maize                                            Composition:         22% anthraquinone                                                             22% captan                                                                    22% carboxin                                             QUINOLATE PRO AC FL ®                                                     SC                                                                            Rate of use:         250 ml/q peas                                            Composition:         200 g/l anthraquinone                                                         120 g/l carbendazim                                                           120 g/l oxine-copper                                     QUINOLATE PLUS MG SAFLO ®                                                 SC                                                                            Rate of use:         400 ml/q cereals                                         Composition:         250 g/l endosulfan                                                            100 g/l gamma-HCH                                                              50 g/l oxine-copper                                     AUSTRAL ®                                                                 SC                                                                            Rate of use:         500 ml/q cereals                                         Composition:         100 g/l anthraquinone                                                          60 g/l oxine-copper                                                           40 g/l tefluthrin                                       GENOIS ®                                                                  WS                                                                            Rate of use:         200 g/q cereals                                          Composition:         25% anthraquinone                                                             10% oxine-copper                                                              10% prochloraz                                           STYLOR T320 ®                                                             SC                                                                            Rate of use:         500 ml/q maize                                           Composition:         320 g/l thiram                                                                210 g/l anthraquinone                                                          15 g/l flutriafol                                       (Tbe above products are available from LA QUINOLEINE Ltd).                    APRON ® (available from the                                               company CIBA-GEIGY Ltd)                                                       WS                                                                            Rate of use:         100 to 600 g/q maize,                                                         peas, sunflower                                          Composition:         35% metalaxyl                                            ______________________________________                                    

or other seed treatment products.

In addition to the active ingredients, the speciality chemicalcompositions may contain:

one or more surface agents comprising a wetting agent and dispersingagent,

one or more dyes or pigments,

inert ingredient(s),

an adhesive agent,

antifreeze,

thickener comprising an antisedimentation and stabilising agent.

The foaming agent is a nonionic, anionic, cationic or amphotericsurfactant or a mixture of two of more of these.

The foaming agents may be chosen especially from:

Nonionic Surfactants

Alkanolamide or alkyloamide e.g. cocarnide diethanolamide, lauric acidmonoisopropanolamide, ethoxylated myristamide.

Fluorocarhons e.g. ethoxylated polyfluorinated alcohol.

Anionic Surfactants

Alkanesulfonate e.g. sodium lauryl sarcosinate.

Alkyl aryl sulfonate e.g. sodium alkylbenzenesulfonate.

Derivatives of (poly)carboxylic acid e.g. ammonium lauryl ethercarboxylate.

Olefin sulfonate e.g. sodium alpha olefin sulfonate.

Sarcosinate e.g. ammonium cyclohexyl palmitoyl taurinate.

Succinate e.g. disodium N-octadecyl sulfosuccinamate.

Phosphorus derivatives e.g. phosphoric acid esters and their equivalentsalts.

Cationic surfactants: e.g. alkylbenzyltrimethylammonium chloride.

Amphoteric surfactants: e.g. betaine.

The foaming agents must not show toxicity to the seed or the plant.

The foam is formed by simultaneously injecting air or gas under pressureinto the composition at the time of application to the seeds.

The gas used can be an inert gas or carbon dioxide. The pressurepreferably varies between 1×10³ and 5×10⁵ Pascals (Pa).

The compositions which enable the process to be carried out thus consistof a composition containing at least one phytoprotection product, andanother composition containing at least one nonphytotoxic foaming agent.

The composition containing the foaming agent can also contain afoam-stabilising agent, preferably the copra diethanolamide.

The composition containing the foaming agent can additionally contain anatural or synthetic resin additive which increases its adhesive power.

Examples of natural resins are:

Alginates--salts and organic derivatives.

Cellulose--hydroxy alkyl-, carboxymethyl- and hydroxypropylethers.

Gums--Carrageenan, Guar, Arabic, Ghatti, Karaya, Tragacanth, LocustBean, Tamarind, Xanthan.

Agar--Polysaccharide.

Pectins.

Examples of synthetic resins are:

Polyacrylamide, polyglycol, polyethylene oxide, polyvinyl alcohol,polyvinyl acetate, polyvinyl pyrrolidone, starch.

The composition containing the foaming agent can contain a colouringagent or pigment in order to demonstrate and assess correct applicationof the process over the whole surface area of the seeds.

The mixing of the elements constituting the composition of the foamingagent can be carried out beforehand and stored until it is applied. Itsapplication is carried out simultaneously with the phytoprotectionproduct via the intermediacy of the different apparatuses:

an apparatus which supplies the composition containing at least onephytoprotection product, and

a second apparatus which causes foam formation, into which thecomposition containing at least one foaming agent and the gas, underpressure, are introduced.

In a preferred embodiment, the phytoprotection product is present in aconcentration of 50 g to 3 kg (or 50 ml to 3 liters if a liquidcomposition) per 100 kg of seeds.

Preferably, the nonphytotoxic foaming agent is a surfactant present in aconcentration of 0.05 g to 100 g per 100 kg of seeds. Particularlypreferred is a concentration of 0.1 to 20 g per 100 kg of seeds.

The present invention also relates to phytoprotection apparatus whichenables the process to be carried out, and which consists of a foamformation apparatus comprising a first foam formation chamber equippedwith openings which allow a gas and the liquid composition to beadmitted and containing, downstream of these openings, at least onesieve, this first chamber continuing into a second chamber forcompressing and structuring the foam, which ends in an outlet nozzle forthe foam, the foam formation apparatus being coupled to a containerequipped with a system for mixing the seeds, the container beingadditionally equipped with an inlet system for the first compositioncontaining the phytoprotection product, through the intermediacy of anozzle or of any apparatus which allows the flow and/or spraying of thissecond composition. The foam thus formed will be applied simultaneouslywith the phytoprotection speciality chemical, for which it serves asvector.

This foam formation apparatus can be combined with conventional seedtreatment apparatus.

In general, seeds will be treated during their passage in a containerconsisting of a rotating-cylinder type mixer or the like, which enablesthem to be mixed uniformly. The system operates continuously, the seedsare bagged directly at the mixer outlet, the drying stage is redundantand it is possible to proceed directly to the bagging stage.

The process can also be carried out in the form of a noncontinuoustreatment.

In one embodiment, the gas inlet and that of the liquid composition arearranged radially, in opposite directions. The introduction is carriedout via the body of separated gas/liquid, dual-inlet nozzles whichconstitute an atomising system. The apparatus contains a circular,wide-angie spraying nozzle immediately adjoining the introductionconnector.

The liquid composition is preferably admitted with a pressure varyingbetween 1×10³ and 5×10⁵ Pa, at a flow rate of between 1 and 500 l/h. Thegas is at a pressure of between 1×10³ and 5×10⁵ Pa.

In another embodiment, the gas inlet and that of the liquid compositionare arranged perpendicularly to one another. The liquid arrives with apressure which can vary between 1×10³ and 5×10⁵ Pa and a deflector isplaced around the liquid inlet system. The ,,as liquid mixture passesthrough an injection nozzle containing a conical chamber and leaves itwith a flow rate of between 1 and 500 liters/hour.

The gas and liquid inlets are fined well upstream of a sieve which isintended to allow foams consisting of very fine bubbles to be obtained.

The apparatus contains a foam formation chamber which contains a sievewhose mesh openings are 250 to 2500 μm in size. The mesh openings may besquare, round or eliptical, and the size refers to to the diameter ordiagonal, depending on the geometry.

In one embodiment, this sieve is generally flat.

In another embodiment, this sieve is frustoconical and is cup-shaped,opening towards the outlet nozzle.

The foam formation chamber can contain, upstream of the sieve of meshsize 250 to 2500 μm, a first sieve having multiform openings of 3 to 10mm. In a particular embodiment, this sieve is in the shape of a smalldish opening towards the means of introduction.

The chamber for compressing and structuring the foam makes it possibleto obtain a foam of thicker consistency.

In one embodiment, the compression chamber is defined by a cylindricalelement situated downstream and in the extension of the main casing ofthe apparatus; this element is fixed by flanges between the casing andan ejection system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents an embodiment of the foam formation apparatusaccording to the invention.

FIG. 2 represents another embodiment of the foam formation apparatusaccording to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

The liquid is admitted under pressure through a tube (2) in a directionperpendicular to that of admission of the air or gas under pressure (6),a joint (4) ensures airtightness. A deflector (8) is interposed betweenthe gas inlet and that of the liquid.

The mixture passes through a full cone nozzle (10) and arrives in thefoam formation chamber (13) on a first sieve (12) with multiformopenings of 3 to 10 mm and then on a second sieve (14) of mesh size 250to 2500 μm. The tube (16) has a total length of 220 mm and a diameter of55 mm.

The mixture then passes into the chamber for compressing and structuringthe foam (18) which continues through a foam outlet nozzle (20) which inuse leads to or is coupled to a seed container (not shown in theFigures) which is equipped with a system for mixing the seeds with thefoam, the seed-mixing container being thus equipped with an inlet systemfor the foam composition which contains the acaricidal, fungicidal,insecticidal or nutritive agent, through the intermediacy of the foamoutlet nozzle (20) or any apparatus which allows the flow and/orspraying of the foamed composition as it exits from the foam outletnozzle (20).

The inlets for liquid (22) and gas or air (24) are arranged along thesame axis and terminate in the body of the dual-inlet nozzle (26). Afterpassing through a circular wide-angle spraying nozzle (28), the mixturearrives in the foam formation chamber (29) on a conical sieve (32) ofmesh size 250 to 2500 μm and 80 mm in length. The conical tube (30) ofdiameter 34 mm and of length 250 mm is fixed by flanges (34) to thechamber for compressing and structuring the foam (36). The foam leavescontinuously through the outlet nozzle (38).

The angles formed between the axes of the inlets 2 and 6 (FIG. 1) and 24and 22 (FIG. 2) are 90° and 180° respectively. The apparatus can also beconstructed in such a way that the angle between the inlet axes is lessthan 90°, e.g. 50°, or between 90° and 180° , e.g. 120°.

According to a preferred embodiment of the process, the compositioncontaining a phytoprotection product and water is introduced into theapparatus and the foam obtained with the surfactant is administeredsimultaneously.

The phytoprotection product is preferably CORMAISON T FL®.

The foaming agent is preferably ethoxylated polyfluoro alcohol.

The treatment slurry containing the phytoprotection composition isintroduced under pressure into a nozzle or with the help of an apparatusfor dispersing into droplets.

The foaming agent is introduced under pressure in a nozzle inlet of theapplicator represented in FIG. 2.

Compressed air is introduced through the other inlet under a pressure of1×10³ to 5×10⁵ Pa. The apparatus is coupled to a screw-type mixer inwhich, for example, maize seeds, of the Jaquar variety, are circulating.

The volume of the foam produced by the process is multiplied by a factorof 50 in relation to that of the equivalent liquid. The treatment iscarded out by continuous spraying over the passing seeds.

A homogeneous treatment of the surface of the pericarp is observed andthe scutellum and the pedicel of the grain are covered, in contrast tothe results obtained with a conventional treatment which covers thesurface of the grain very unequally. There is virtually no increase inthe moisture content.

This confirms well the improvement in the covering and penetrating powerof the gas/liquid interfacial treatment, which makes it possible to usea limited quantity of liquid. A continuous film is formed around theseeds, without significant water contribution, by virtue of thesimultaneous addition of a composition which contains a surfactant withthe application of the seed treatment slurry used in the conventionalfashion. The retention of phytoprotection products on the treated seedsis increased. The relative pesticidal power of an active ingredient isthus found to be increased.

Many variants, not essentially different in the quantities and qualitiesused, may be readily envisaged and are thus contained within the scopeof the present invention.

Many adaptations are possible depending on the output required. Frompreliminary industrial trials it was found that the dimensions of theapplicator must be adapted to the required hourly output.

The examples below illustrate the advantages of the phytoprotectionprocess in accordance with the invention applied to wheat and maize,sunflower and pea seeds.

EXAMPLE 1

Wheat species Variety: Fidel

Quantity treated: 25 kg--application by spraying

Mixer: 150 liter cement mixer

Slurry preparation for 100 kg of seeds.

    ______________________________________                                        Conventional method (1)                                                       QUINOLATE + AC FL ® 250        ml                                         Water                   500        ml                                         Method according to the invention (2)                                         Phytoprotection composition by spraying                                       QUINOLATE + AC FL ® 250        ml                                         Water                   250        ml                                         Foaming agent composition:                                                    sodium salt of alpha    0.1 to 10  g                                          C.sub.14 -C.sub.16 olefin sulfate                                             copra diethanolamide    0.1 to 5   g                                          water                   250        ml                                         compressed air                                                                applicator 1                                                                  Total volume obtained:                                                        According to Method 1   750        ml                                         According to Method 2   5000-10,000                                                                              ml                                         Microscopic observations:                                                     Conventional method (1)                                                       Surface heterogeneously treated,                                              Noncontinuous film,                                                           Negligible impact in the furrow of the seed.                                  Method according to the invention (2)                                         Surface uniformly treated,                                                    Continuous film,                                                              Seed furrow 90% covered.                                                      Moisture content of the grains:                                               Before treatment: 15.5%                                                       After treatment: (1) 16.1% (2) 16%                                            Example 2                                                                     Wheat species Variety: Fidel                                                  Conventional method (1) by flowing                                            QUINOLATE + AC FL ® 250        ml                                         Water                   500        ml                                         Method according to the invention (2)                                         Phytoprotection composition (by flowing)                                      QUINOLATE + AC FL ® 250        ml                                         Water                   250        ml                                         Foaming agent composition:                                                    Na salt of alpha        0.1 to 20  g                                          C.sub.14 -C.sub.16 olefin sulfate                                             Water                   250        ml                                         Cochineal red           25         g                                          Compressed air                                                                Applicator No. 1                                                              Total volume obtained:                                                        Method 1                750        ml                                         Method 2                4000 to 8000                                                                             ml                                         ______________________________________                                    

Microscopic observations of the treated grains:

Conventional method (1)

Surface heterogeneously treated,

Impacts,

Very few impacts in the furrow.

Method according to the invention (2)

Surface uniformly treated,

Continuous film,

Furrow 90% covered.

Moisture content of the grains:

Before treatment: 15.2%

After treatment: (1) 15.7% (2) 15.9%

The quantities of products indicated are expressed in grams ormilliliters per 100 kg of seeds.

EXAMPLE 3

Maize species Variety: Jaquar (toothed half-flat)

Quantity treated: 1000 kg--application by flow

Mixer: screw-type, length 180 cm.

Slurry preparation per 100 kg of seeds.

    ______________________________________                                        Conventional method (1)                                                       CORMAISON T FL ®   500        ml                                          Water                  500        ml                                          Method according to the invention (2)                                         Phytoprotection composition                                                   CORMAISON T FL ®   500        ml                                          Water                  250        ml                                          Foaming agent composition                                                     Ethoxylated polyfluoro alcohol                                                                       0.1-10     g                                           Copra diethanolamide   0.1-5      g                                           Water                  250        ml                                          Applicator No. 2                                                              Compressed air                                                                Volumes obtained:                                                             Method 1:              1000       ml                                          Method 2:              8000 to 10,000                                                                           ml                                          ______________________________________                                    

Microscopic observations:

Conventional method (1)

Surface heterogeneously treated,

Noncontinuous film,

Few impacts on the comet and the hilum.

Method according to the invention (2)

Continuous film,

Comet uniformly treated,

Hilum uniformly treated.

Moisture content of the grains:

Before treatment: 13%

After treatment: (1) 13.8% (2) 13.9%

EXAMPLE 4

Maize species Variety: Jaquar (toothed half-flat)

Quantity treated: 2000 kg--application by continuous spraying on thepassing grains.

Mixer: screw-type, length 180 cm.

Slurry preparation per 100 kg of seeds.

    ______________________________________                                        Conventional method (1):                                                      Cormaison T FL          500      ml                                           Water                   500      ml                                           Volume obtained         1000     ml                                           Method according to the invention (2):                                        Phytoprotection composition                                                   Cormaison T FL          500      ml                                           Water                   250      ml                                           Foaming agent composition                                                     Ethoxylated polyfluoro alcohol                                                                        0.2 to 20                                                                              g                                            Cochineal red           25       g                                            Polyethylene glycol M 6000                                                                            50       g                                            Water                   250      ml                                           Applicator No. 2                                                              Compressed air                                                                ______________________________________                                    

Volumes obtained

Method 1 1000 ml

Method 2 12,000 to 15,000 ml

Microscopic observations:

Conventional method (1):

Surface heterogeneously treated,

Many impacts on the pericarp only,

Few impacts on the scutellum.

Method according to the invention (2):

Surface of the pericarp homogeneously treated,

Scutellum and pedicel covered.

Moisture content:

Before treatment: 13%

After treatment: (1) 13.7% (2) 13.9%

The quantities of product indicated are expressed in grams ormilliliters per 100 kg of seeds.

CORMAISON T

    ______________________________________                                        Composition based on                                                                             266 g/l thiram                                                                175 g/l anthraquinone                                      ______________________________________                                    

EXAMPLE 5

In order to verify the homogeneity of the treatment according to theprocess of the present invention, a batch of seeds of wheat of the Fidelvariety may be treated according to the two application methods asdescribed in Example 2.

In order to analyse the quantity of active material (oxine-copper) oneach grain, the sampling may be carried out according to the La Croixmethod until±100 grains are obtained.

    ______________________________________                                        Analytical method:                                                            ______________________________________                                        Atomic absorption of the copper using a SPECTRA AA 10                         spectrometer.                                                                 Extraction: Ultrasound -- acidified water (HCl)                               Number of grains analysed:                                                                    Conventional method (1): 98                                                   Method according to the invention                                             (2): 101                                                      ______________________________________                                    

                  TABLE 1                                                         ______________________________________                                        Result expressed as a percentage of the theoretical treatment.                Treatment in relation                                                         to the theory     Number of grains                                            100%              Method 1 Method 2                                           ______________________________________                                         <70%             21        0                                                 70% to 90%        33        6                                                  90% to 100%      30       86                                                 110% to 130%      10        8                                                 >130%              4        1                                                 TOTAL             98       101                                                ______________________________________                                    

EXAMPLE 6

Verification of the absence of phytotoxicity in the foaming agents used.

Germination trials are carried out on seeds treated respectively asdescribed in Examples 2 and 4. The vigour of the seed is recordedthrough an index ranging from 1 to 5 (5 being the highest index).

Method: folded filter paper

Temperature: 20° C.±0.5° C.

Reading: 8 days after sowing

Moisture content: 95%

Repetitions: 4×100 grains

                  TABLE 2                                                         ______________________________________                                        Result on wheat seeds, Fidel variety,                                         treated according to Example 2.                                                      AVERAGE OF THE 4 REPETITIONS                                                            Ab-     LC*                                                             Deaths                                                                              normal  %                                                           Vigour                                                                              %       %       <2 cm >2 cm >7 cm                                ______________________________________                                        Conventional                                                                           5       1.25    2.25  0     1     95.5                               method (1)                                                                    Method   5       1.75    1     0.25  2     95                                 according                                                                     to the                                                                        invention (2)                                                                 ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                        Result on Jaquar maize seeds treated according to Example 4.                         AVERAGE OF THE 4 REPETITIONS                                                            Ab-     LC*                                                             Deaths                                                                              normal  %                                                           Vigour                                                                              %       %       <2 cm >2 cm >7 cm                                ______________________________________                                        Conventional                                                                           5       1       1.5   0.5   8     89                                 method (1)                                                                    Method   5       0.5     1     1     7.5   90                                 according                                                                     to the                                                                        invention (2)                                                                 ______________________________________                                         *percentage of grains which, after germination, have a coleoptile length      (LC) in the ranges indicated.                                            

EXAMPLE 7

Verification of the moisture content expressed in percentage by weightand analysed according to the Chopin method.

Methods used:

A--noncontinuous soaking in water containing a phytoprotection product

B--noncontinuous soaking in a foam formed from a mixture of water,foaming agent and the phytoprotection product. Degree of expansion: 20times

C--by continuous or noncontinuous spraying, according to theconventional methods, with water containing a phytoprotection product

D--by spraying composition 1 plus composition 2 according to the methoddescribed in the invention. Degree of expansion: 20 times.

Table 4 (below) illustrates results expressed as a percentage of wateruptake.

                  TABLE 4                                                         ______________________________________                                        Results expressed as a percentage of water uptake                                          Moisture content in %                                                         Wheat (varieties)                                                                             Barley                                           Method                      Maris        Barba-                               used               Theseus  Huntsman                                                                              Fidel                                                                              rossa                                ______________________________________                                               Before Soaking                                                                            11.4     12.2    12.6 13.8                                        or Spraying                                                            A      Soaking  5 sec.                                                                           24.7     24.6    24.3 25.4                                        Soaking 10 sec.                                                                           26.6     25      25.1 27.2                                        Soaking 20 sec.                                                                           27.2     26      25.4 28.4                                 B      Soaking  5 sec.                                                                           16.6     19.4    22   19.1                                        Soaking 10 sec.                                                                           16.3     19.2    21.5 20.7                                        Soaking 20 sec.                                                                           18.4     23.5    24.2 23.9                                 C      Spraying 11*                                                                              12.2     13.0    13.4 14.7                                  C1    Spraying 21*                                                                              13.1     14.1    14.4 15.6                                 D      Spraying 11*                                                                              12.3     13      13.4 14.7                                  D1    Spraying 21*                                                                              13.2     13.9    14.3 15.5                                 ______________________________________                                         *1 or 21 per 100 kg of grains, for trials C and D                             10 or 20 ml per 1 kg of grains                                           

                  TABLE 5                                                         ______________________________________                                        Increase in weight                                                            Trial sample: 10 kg of grains                                                 Soaking time: 10 sec.                                                         Spraying time                                                                 per 100 ml: 10 sec.                                                           per 200 ml: 20 sec.                                                           Results expressed in kilograms                                                               C         D                                                    Variety    A      B      100 ml                                                                              200 ml                                                                              100 ml                                                                              200 ml                             ______________________________________                                        Wheat Thesius  11.52  10.49                                                                              10.08 10.19 10.08 10.18                                  Maris    11.30  10.70                                                                              10.09 10.18 10.09 10.19                                  Hunts-                                                                        man                                                                           Fidel    11.25  10.69                                                                              10.09 10.19 10.09 10.18                            Barley                                                                              Barba-   11.40  10.69                                                                              10.09 10.18 10.08 10.08                                  rossa                                                                   ______________________________________                                    

We claim:
 1. An apparatus for a process for wet-treating seeds with anacaricidal, fungicidal, insecticidal or nutritive agent which consistsof a foam-formation apparatus comprising a first foam-formation chamber(13;29) equipped with a gas inlet (6;24) and an aqueous compositioninlet, said composition containing at least a nonphytotoxic foamingagent (2;22)) to be admitted and containing, downstream of theseopenings, at least one sieve (14;32), this first chamber continuing intoa second chamber for compressing and structuring the foam (18;36), whichsecond chamber ends in an outlet nozzle for the foam (20;38).
 2. Anapparatus according to claim 1, wherein the gas inlet (24) and that ofthe composition containing the foaming agent (22) are arranged radiallyin opposite directions.
 3. A phytoprotection apparatus containing a foamformation chamber according to claim 2, wherein the a sieve (14; 32)mesh openings are 250 to 2500 mm in size.
 4. An apparatus according toclaim 1, wherein the gas inlet (6) and that of the compositioncontaining a foaming agent (2) are arranged perpendicularly to oneanother.
 5. A phytoprotection apparatus containing a foam formationchamber according to claim 4, wherein the a sieve (14; 32) mesh openingsare 250 to 2500 mm in size.
 6. An apparatus according to claim 1,wherein the sieve has (14; 32) mesh openings of 250 to 2500 μm in size.7. An apparatus according to claim 6, wherein the apparatus contains twosieves, one of the sieves (12) having multiform openings of 3 to 10 mmand being upstream of another sieve (14) having a mesh size in the rangeof 250 to 2500 μm.